loginfilter.java

用户可以添加商品

package product.filter; 

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

public class LoginFilter implements Filter{
	public void init(FilterConfig filterConfig)
          throws ServletException{
    }
    
    public void doFilter(ServletRequest request,
                     ServletResponse response,
                     FilterChain chain)
              throws java.io.IOException,ServletException{
        HttpServletRequest r = (HttpServletRequest)request;
        HttpServletResponse s = (HttpServletResponse)response;
    	String uid = (String)r.getSession().getAttribute("uid");
    	if(uid==null){
    		r.setAttribute("targetPage",r.getRequestURI());
 			r.setAttribute("login","请先登录");
    		r.getRequestDispatcher("/index.jsp").forward(r,s);
    		return;
    	}
    	chain.doFilter(request,response);
	}
	
	public void destroy(){	
	}
}